By Victoria Cavaliere(Reuters) - Eight people were injured, one of them seriously, after an explosion and fire struck a U.S. Navy ammunitions depot near the New Jersey shore on Tuesday, Navy officials said.Fire trucks, ambulances and a medical emergency helicopter rushed to Naval Weapons Station Earle, located near Colts Neck Township, about 45 miles from Manhattan. The cause of the explosion at a Marine boat repair shop at about 9 a.m. EDT was being investigated."The damage from the explosion was contained within the boathouse area. Ammunition and ordnance operations at the weapons station were not affected by the accident," the Navy said in a statement.The injured included seven sailors and one civilian, said base spokesman Mike Brady.One of the injured was seriously hurt and taken by medical helicopter to a local hospital for treatment, though the type of injuries sustained were still unknown, he said. The seven others suffered minor injuries, including smoke inhalation.The explosion occurred during routine maintenance on a 35-foot utility boat and the blast ripped apart both the vessel and much of the adjoining building, Brady said.A base firehouse is located next door to the boat repair shop and was able to respond "almost immediately," he said.Brady said the stores of ammunition on the base are kept in an area separate from where boats are serviced and the explosion posed no threat to the adjoining community.The base, which has a workforce of 1,500 people, has several facilities located in Colts Neck and surrounding towns, according to the U.S. Navy website. It serves as the "operational support base for five Military Sealift Commands combat logistics ships," according to the website.